Implementing deposition growth method for magnetic memory

ABSTRACT

A magnetic memory array and a method for implementing the magnetic memory array for use in Solid-State Drives (SSDs) are provided. A plurality of magnetic pillar memory cells is formed using a deposition and/or growth process to produce a magnetic memory array substantially avoiding milling of magnetic materials.

This application is a divisional application of Ser. No. 14/835,271filed Aug. 25, 2015

RELATED APPLICATIONS

A related application by the present assignee and inventors is beingfiled on Aug. 25, 2015 having Ser. No. 14/834,743, and entitled“IMPLEMENTING ENHANCED MAGNETIC MEMORY CELL”.

A related application by the present assignee and inventors is beingfiled on Aug. 25, 2015 having Ser. No. 14/834,856, and entitled“IMPLEMENTING MAGNETIC MEMORY PILLAR DESIGN”.

A related application by the present assignee and inventors is beingfiled on Aug. 25, 2015 having Ser. No. 14/834,929, and entitled“IMPLEMENTING 3D SCALABLE MAGNETIC MEMORY”.

A related application by the present assignee and inventors is beingfiled on Aug. 25, 2015 having Ser. No. 14/835,021, and entitled“IMPLEMENTING MAGNETIC MEMORY INTEGRATION WITH CMOS DRIVING CIRCUITS”.

A related application by the present assignee and inventors is beingfiled on Aug. 25, 2015 having Ser. No. 14/835,543, and entitled“IMPLEMENTING SEGREGATED MEDIA BASED MAGNETIC MEMORY”.

This application is a divisional application of Ser. No. 14/835,271filed Aug. 25, 2015.

FIELD OF THE INVENTION

The present invention relates generally to the data storage field, andmore particularly, relates to a magnetic memory array and a method forimplementing the magnetic memory array for use in Solid-State Drives(SSDs).

DESCRIPTION OF THE RELATED ART

Typically NAND flash memory is the solid-state non-volatile memory usedin Solid-State Drives (SSDs). Several alternative non-volatile memorytechnologies have been proposed. Phase-Change Memory (PCM) and ResistiveRAM are two of those alternative technologies which received significantattention and are both considered emerging technologies.

A disadvantage of currently available solid-state non-volatile memorytechnologies is low endurance limits of program/erase cycles. Also insome known solid-state non-volatile memory technologies, there is atradeoff between retention and power to program, and there is a tradeoffbetween power to program and endurance through a reliability dependence.

A need exists for effective mechanism for implementing a magnetic memoryarray for use in Solid-State Drives (SSDs).

SUMMARY OF THE INVENTION

Aspects of the preferred embodiments are to provide a magnetic memoryarray and a method for implementing the magnetic memory array for use inSolid-State Drives (SSDs). Other important aspects of the preferredembodiments are to provide such magnetic memory array and methodsubstantially without negative effect and to overcome some of thedisadvantages of prior art arrangements.

In brief, a magnetic memory array and a method for implementing themagnetic memory array for use in Solid-State Drives (SSDs) are provided.A plurality of magnetic pillar memory cells is formed using depositionand/or growth process to produce a magnetic memory array substantiallyavoiding milling of magnetic materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention together with the above and other objects andadvantages may best be understood from the following detaileddescription of the preferred embodiments of the invention illustrated inthe drawings, wherein:

FIGS. 1A and 1B respectively illustrate a vertical channel constructionand a horizontal channel construction of electrically equivalentmagnetic memory cells in accordance with preferred embodiments;

FIGS. 2A and 2B respectively illustrate programming magnetization up andmagnetization down of the vertical channel magnetic memory cell of FIG.1A in accordance with preferred embodiments;

FIGS. 3A and 3B respectively illustrate programming magnetization up lowresistance state readout operation and magnetization down highresistance state readout operation of the vertical channel magneticmemory cell of FIG. 1A in accordance with preferred embodiments;

FIGS. 4A and 4B respectively illustrate programming magnetization uphigh resistance state high contrast readout operation and magnetizationdown low resistance state readout operation of the vertical channelmagnetic memory cell of FIG. 1A in accordance with preferredembodiments;

FIGS. 5A and 5B respectively illustrate a vertical channel constructionand a horizontal channel construction of electrically equivalentmagnetic memory cells with multiple wordlines in accordance withpreferred embodiments;

FIGS. 6A and 6B respectively illustrate programming magnetization up andmagnetization down of the vertical channel magnetic memory cell of FIG.5A in accordance with preferred embodiments;

FIGS. 7A and 7B respectively illustrate programming magnetization up lowresistance state and magnetization down high resistance state of thevertical channel magnetic memory cell of FIG. 5A in accordance withpreferred embodiments;

FIGS. 8A and 8B respectively illustrate programming magnetization uphigh resistance state and magnetization down low resistance state of thevertical channel magnetic memory cell of FIG. 5A in accordance withpreferred embodiments;

FIGS. 9A, 9B and 9C respectively illustrate use of revolution around thevertical axis to construct a vertical one dimensional (1) arrayembodiment of magnetic memory cells using of the vertical channelmagnetic memory cell of FIG. 5A in accordance with preferredembodiments;

FIG. 10 illustrates a two dimensional (2D) plane extended to construct avertical three dimensional (3D) array embodiment of magnetic memorycells using of the vertical channel magnetic memory cell of FIG. 5A inaccordance with preferred embodiments;

FIGS. 11A and 11B respectively illustrate a magnetic memory threedimensional (3D) array embodiment of magnetic memory cells using aninterlayer dielectric (IDL) stack in accordance with preferredembodiments;

FIGS. 12A, 12B and 12C illustrate a three dimensional (3D) arrayembodiment of magnetic memory cells showing respective example steps tocreate one contact per wordplane in accordance with preferredembodiments;

FIGS. 13A, 13B and 13C and FIGS. 14A, 14B, 14C, 14D, and 14E illustraterespective example paths for integration of the three dimensional (3D)array embodiment of magnetic memory cells onto a complementary metaloxide semiconductor (CMOS) wafer in accordance with preferredembodiments;

FIGS. 15A, 15B, 15C, 15D, and 15E illustrate example steps for growingmagnetic memory cells on a complementary metal oxide semiconductor(CMOS) wafer in accordance with preferred embodiments;

FIGS. 16A, and 16B illustrate example segregated media based silomagnetic media in accordance with preferred embodiments;

FIGS. 17A, and 17B illustrate an example detailed side view of avertical pillar channel magnetic memory of memory cells in accordancewith preferred embodiments;

FIGS. 18A, 18B, 18C, 18D and 18E illustrate example alternationmagnetization variations of biased elements of the vertical pillarchannel magnetic memory of FIGS. 17A, and 17B in accordance withpreferred embodiments;

FIG. 19 illustrates an example detailed top view of a vertical pillarchannel magnetic memory of memory cells in accordance with preferredembodiments;

FIGS. 20A, and 20B illustrate example alternation magnetizationvariations of biased elements of the vertical pillar channel magneticmemory of FIGS. 21 and 22 in accordance with preferred embodiments; inaccordance with preferred embodiments; and

FIGS. 21 and 22 illustrate example detailed top views of a segregatedmedia in layer M1 of vertical pillar channel magnetic memory of memorycells in accordance with preferred embodiments in accordance withpreferred embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following detailed description of embodiments of the invention,reference is made to the accompanying drawings, which illustrate exampleembodiments by which the invention may be practiced. It is to beunderstood that other embodiments may be utilized and structural changesmay be made without departing from the scope of the invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

In accordance with features of the preferred embodiments, a magneticmemory array and a method for implementing the magnetic memory array,for example, for use in Solid-State Drives (SSDs) are provided. Aplurality of magnetic pillar memory cells is formed using a depositionand/or growth process to produce a magnetic memory array substantiallyavoiding milling of magnetic materials. A magnetic memory cell, forexample, for Storage Class Memory (SCM) applications, includesprogrammable area with unpatterned programmable magnetic media. Themagnetic memory cell is programmed in at least one of its magnetizationstates by a spin-biased steered current or spin-biased tunnelingcurrent. The magnetization state of the magnetic memory cell is sensedin a readout operation, for example, with steered currents in a lowcontrast readout operation or, for example, with tunneling currents in ahigh contrast readout operation. The magnetic memory cell is capable ofhigh endurance, low power and adequate retention in variousapplications.

Drawings are shown in simplified form sufficient for understanding thepreferred embodiments. Those skilled in the art will notice thatreferences to a spacer layer between magnetic layers is frequentlyomitted in the drawings and textual description. The need for such alayer is assumed to be understood by those skilled in the art and it isonly in the interest of simplifying the drawings only that the spacer isomitted in the figures described below.

Having reference now to the drawings, FIGS. 1A and 1B respectivelyillustrate a vertical channel construction and a horizontal channelconstruction of electrically equivalent magnetic memory cells inaccordance with preferred embodiments. In FIGS. 1A and 1B, there areshown example respective magnetic memory cell designs generallydesignated by the reference character 100, 110 having a vertical channelconstruction, and having a horizontal channel construction.

In FIG. 1A, the magnetic memory cell 100 includes programmable areausing programmable magnetic media including a first conductor 102, M1,and a second conductor 104, M2. Optionally the conductors 102, M1, 104,M2 are formed of magnetic materials, and the conductor 104, M2 is moreconductive than conductor 102, M1. Conductor 104, M2 is designed to havea permanent magnetization direction, such as indicated by an arrow A,whereas conductor 102, M1 is programmable in either parallel oranti-parallel magnetization states, such as indicated by respectivearrows B and C. A wordline 106 is provided with a suitable oxide ortunneling barrier 107 for electric current flow between the magneticwordline 106 and the channel conductor 102, M1. A line 108 extendsbetween the conductors 102, M1, 104, M2 toward a bitline.

In FIG. 1B, the magnetic memory cell 110 includes programmable areausing programmable magnetic media including a first conductor 112, M1,and a second conductor 114, M2. The conductors 112, M1, 114, M2optionally are formed of magnetic materials, and the conductor 114, M2is more conductive than conductor 112, M1. Conductor 114, M2 is designedto have a permanent magnetization direction, such as indicated by anarrow A, whereas conductor 112, M1 is programmable in either parallel oranti-parallel magnetization states, such as indicated by respectivearrows B and C. A wordline 116 is provided with a suitable oxide ortunneling barrier 117 for electric current between the magnetic wordline116 and the channel conductor 112, M1. A line 118 extends between theconductors 102, M1, 104, M2 toward a bitline.

In accordance with features of the preferred embodiments, conductor 104,M2, and conductor 114, M2 is optionally formed of a non-magneticmaterial, preferably Tantalum (Ta) with spin orbital coupling effects.Conductor 104, M2, and conductor 114, M2 being formed of a magneticmaterial provides better filtering of spin directions in operation ofthe magnetic memory cells 100, 110. For example, tantalum (Ta) is used,to form conductor 104, M2, and conductor 114, M2 instead of a magneticmaterial. The use of tantalum is an effective choice if the Spin HallEffect (SHE) is strong enough in an implementation. If the SHE intantalum is a strong enough effect, instead of filtering spins, tantalumcan provide a spin current that will also torque the programmable M1area. The magnetic conductor M2 can be used to filter electrons withspin that could torque the magnetization in the programmable conductorM1.

In accordance with features of the preferred embodiments, vertical andhorizontal constructions of the magnetic memory cell 100, 110 areelectrically equivalent, while enabling different advantages infabrication processes. The horizontal construction of magnetic memorycell 110 potentially is easier to realize in a one-cell demonstration ofconcept, while the vertical construction of magnetic memory cell 100 mayprove more suitable for an advantageous three dimensional (3D) arraystructure of those magnetic memory cells.

In accordance with features of preferred embodiments, the magneticmaterials in conductor 102, M1, 104, M2 advantageously are notpatterned. The association of conductors 102, M1, 104, M2 are referredto as totem. Note that in the vertical direction as shown in FIGS. 1Aand 1B this totem optionally is constructed by deposition of materialsin etched hole or silo, hence the name silo memory.

In accordance with features of preferred embodiments, because thevertical and horizontal constructions of the magnetic memory cells 100,110 are electrically equivalent, programming and reading operations aredescribed using the vertical construction of the magnetic memory cell100.

In accordance with features of the preferred embodiments, memory cell100 includes an unpatterned suitable oxide/barrier and non-queried celltransparency. Electrically controlled stress/strain is used by means ofthe unpatterned oxide/barrier suitable to affect ease of programmabilityand low power. Memory cell 100 includes an unpatterned programmable cellarea. Steering of current for programming a memory cell and steering ofspin-polarized current for reading a memory cell are provided.Combination of programming with a spin polarized steered current or aspin polarized tunneling current optionally is provided.

Referring to FIGS. 2A and 2B, there are shown respective exampleprogramming magnetization up generally designated by the referencecharacter 200 and magnetization down generally designated by thereference character 210 of the vertical channel magnetic memory cell 100of FIG. 1A in accordance with preferred embodiments. It should beunderstood that FIGS. 2A and 2B provide example operations, and oneskilled in the art will recognize other variations can be found withoutdeparting from the spirit of the preferred embodiments. Current in thevertical totem prefers to stay in the more conductive conductor 104, M2.

In FIG. 2A, programming the state of magnetization up in the design 100is performed by steering the spin-biased current in the totem into theprogrammable conductor 102, M1 in the area immediately adjacent to thewordline gate 106, 107. The line 108 extends between the conductors 102,M1, 104, M2 toward a bitline. In FIG. 2B, programming the state ofmagnetization down in the design 100 is performed by steering thespin-biased tunneling current flowing from the totem to the wordlinegate 106 through the suitable oxide or barrier 107.

In accordance with features of the preferred embodiments, reading can beaccomplished by two different methods. Method 1, shown in FIGS. 3A and3B is referred to as low contrast read out operations. Method 2, shownin FIGS. 4A and 4B, is referred to as high contrast read out operations.

Referring to FIGS. 3A and 3B, there are shown example magnetization uplow resistance state reading operation generally designated by thereference character 300 and magnetization down high resistance statereading operation generally designated by the reference character 310 ofthe vertical channel magnetic memory cell 100 of FIG. 1A in accordancewith preferred embodiments. In FIGS. 3A and 3B, the line 108 extendingbetween the conductors 102, M1, 104, M2 is connected to a bitline 302and a reference 304 is shown. A resistor 306 connects line 108 andbitline 302 to a voltage supply V.

In accordance with features of preferred embodiments, in the lowcontrast readout operations 300, 310 of FIGS. 3A and 3B, the state ofmagnetization of memory cell 100 is sensed by steering current flowingin the vertical totem towards the programmed magnetic area. Note that arobust self-referenced algorithm for readout can include a multiple stepself-referenced operation where the cell is first sensed, then writtento a known content, and then sensed again. The difference between thosesensed state readouts then used to determine the original cell content.In such a multiple step readout operation the original content may bedestroyed and the cell might need to be rewritten after the being read.

Referring to FIGS. 4A and 4B, there are shown example magnetization uphigh resistance reading operation generally designated by the referencecharacter 400 and magnetization down low resistance state readingoperation generally designated by the reference character 410 of thevertical channel magnetic memory cell 100 of FIG. 1A in accordance withpreferred embodiments. FIGS. 4A and 4B shows the high contrast readoutoperation including a switch 402 between a ground potential connectionand line 108 and bitline 302.

In accordance with features of preferred embodiments, in the highcontrast readout operations 400, 410 of FIGS. 4A and 4B, the content ofthe magnetic cell 100 is sensed by spin-biased current flowing throughthe suitable oxide or barrier 107. Similar to the case of low contrastreadout, a robust multiple step for readout, which is self-referenced,can be conceived with a readout operation, followed by a programoperation to a known magnetization state, and a second readoutoperation. The cell content thus determined by the difference betweenthe two readout operation results.

In accordance with features of preferred embodiments, in both low andhigh readout operations the level of current used must be low enough notto soft program the memory cell sensed.

FIGS. 5A and 5B respectively illustrate a vertical channel constructiongenerally designated by the reference character 500 and a horizontalchannel construction generally designated by the reference character 512of electrically equivalent one dimensional (1D) array magnetic memorycells with multiple wordlines in accordance with preferred embodiments.

In FIG. 5A, the magnetic memory cell array 500 includes programmablearea using programmable magnetic media including a first conductor 502,M1, and a second conductor 504, M2. The conductors 502, M1, 504, M2 areformed of magnetic materials, and the conductor 504, M2 is moreconductive than conductor 502, M1. Conductor 504, M2 is designed to havea permanent magnetization direction, such as indicated by an arrow A,whereas conductor 502, M1 is programmable in either parallel oranti-parallel magnetization states, such as indicated by respectivearrows B and C. A plurality of wordlines 506 is provided with a suitableoxide or tunneling barrier 507 for electric current between the magneticwordlines #1-N, 506 and the channel conductor 502, M1. A line 508extends between the conductors 502, M1, 504, M2 toward a bitline.

In FIG. 5B, the magnetic memory cell array 510 includes programmablearea using programmable magnetic media including a first conductor 512,M1, and a second conductor 514, M2. The conductors 512, M1, 514, M2optionally are formed of magnetic materials, and the conductor 514, M2is more conductive than conductor 512, M1. Conductor 514, M2 is designedto have a permanent magnetization direction, such as indicated by anarrow A, whereas conductor 512, M1 is programmable in either parallel oranti-parallel magnetization states, such as indicated by respectivearrows B and C. A plurality of wordlines #1-N, 516 is provided with asuitable oxide or tunneling barrier 517 for electric current between themagnetic wordlines 516 and the channel conductor 512, M1. A line 518extends between the conductors 512, M1, 514, M2 toward a bitline.

In accordance with features of preferred embodiments, the magneticmemory cell array 500 and magnetic memory cell array 510 areelectrically equivalent but imply different advantages in fabricationprocesses. The horizontal construction may be easier to realize in ademonstration of concept, but the vertical construction may prove moresuitable for an advantageous 3D array structure of those magnetic memorycells. Because the vertical and horizontal constructions areelectrically equivalent, programming and reading operations aredescribed respectively using the vertical construction in FIGS. 6A and6B, and FIGS. 7A and 7B and FIGS. 8A and 8B.

FIGS. 6A and 6B respectively illustrate programming magnetization upgenerally designated by the reference character 600 and magnetizationdown of the vertical channel magnetic memory cell array of FIG. 5A inaccordance with preferred embodiments. FIGS. 6A and 6B illustrate anexemplifying design, while the skilled in the art will recognize othervariations can be found without departing from the spirit of thepreferred embodiments. Current in the vertical totem prefers to stay toin the more conductive conductor 504, M2. Programming the state ofmagnetization up in the design 600 of FIG. 6A is performed by steeringthe spin-biased current in the totem into the programmable conductor502, M1 in the area immediately adjacent to the wordline gate 506.Programming the state of magnetization down in the design 612 of FIG. 6Bcan be accomplished by the spin-biased tunneling current flowing fromthe totem to the wordline gate 506 through the suited oxide or barrier507 which includes a pair of switches 612, 614 respectively connectedbetween line 508 and the voltage rail V and ground and where −−indicates a more negative voltage than −.

In accordance with features of preferred embodiments, note that currentflow through the totem without affecting the non-queried memory cells.This feature of the array to allow a shared media for programming any ofthe cells in the array without disturbing the non-queried cells isreferred to as a feature allowing for the non-queried cells to becometransparent. Also, the unpatterned layer of the suitable oxide/barrier507 allows for adding the feature of electrically controlling thestress/strain imposed on the area of conductor 502, M1 to be programmedwith the effect of easing programming, or lowering the current levelsneeded for programming.

FIGS. 7A and 7B respectively illustrate programming magnetization up lowresistance state low contrast readout operation generally designated bythe reference character 700 and magnetization down high resistance statelow contrast readout operation generally designated by the referencecharacter 710 of the vertical channel magnetic memory cell 500 of FIG.5A in accordance with preferred embodiments. FIGS. 7A and 7B illustratea bitline 702 connected to line 508, a reference 704, and a resistor 706connected between the bitline 702 and voltage rail V.

In accordance with features of preferred embodiments, in the lowcontrast readout operations of FIGS. 7A and 7B, the state ofmagnetization of memory cell is sensed by steering current flowing inthe vertical totem towards the programmed magnetic area. Note that arobust self-referenced algorithm for readout can include a multiple stepoperation where the cell is first sensed, then written to a knowncontent, and then sensed again. The difference between those sensedstate readouts is used to determine the original cell content. In such amultiple step readout operation the original content may be destroyedand the cell might need to be rewritten after the being read.

FIGS. 8A and 8B respectively illustrate programming magnetization uphigh resistance state high contrast readout operation generallydesignated by the reference character 800 and magnetization down lowresistance state high contrast readout operation generally designated bythe reference character 810 of the vertical channel magnetic memory cell500 in accordance with preferred embodiments. FIGS. 8A and 8B illustratea bitline 702 connected to line 508, a reference 704, and a resistor 706connected between the bitline 702 and voltage rail V, and a switch 802connected between line 508 and ground potential.

In accordance with features of preferred embodiments, in the highcontrast readout operations of FIGS. 8A and 8B, the content of themagnetic cell is sensed by spin-biased current flowing through thesuitable oxide or barrier 507. Similar to the case of low contrastreadout operations of FIGS. 7A and 7B, a robust multiple step forreadout, which is self-referenced, can be used with the readoutoperation, followed by a program operation to a known magnetizationstate, and a second readout operation. The cell content thus determinedby the difference between the two readout operation results.

In accordance with features of preferred embodiments, in both low andhigh readout operations of FIGS. 7A and 7B, and FIGS. 8A and 8B, thelevel of current used must be low enough not to soft program the memorycell sensed.

FIGS. 9A, 9B and 9C respectively illustrate use of revolution around thevertical axis to construct a vertical one dimensional (1D) arrayembodiment of magnetic memory cells using of the vertical channelmagnetic memory cell 500 in accordance with preferred embodiments.

In accordance with features of preferred embodiments, in FIG. 9A astarting construct generally designated by the reference character 900is shown of the magnetic memory cell array 500 with multiple wordlines506. In FIG. 9B, a next construct generally designated by the referencecharacter 910 is shown extending oxide 912. In FIG. 9C, a next constructgenerally designated by the reference character 920 includes extendingmagnetic leads 914 and make one revolution indicated by arrow R.Conductive materials 502, M1 are deposited on walls of a hole 916. Thelayers defining magnetic leads 914 are deposited before the hole 916.

FIG. 10 illustrates a vertical three dimensional (3D) array embodimentgenerally designated by the reference character 1000 from the construct920 extended on a two dimensional (2D) plane or word plane 1002 inaccordance with preferred embodiments. In FIG. 10, the magnetic leads orwordlines 914 are extended to the word plane 1002.

In accordance with features of preferred embodiments, a 3D array 1000can be constructed with a single critical etching step for all thevertical totems followed by deposition of a suitable oxide/barrier andmagnetic materials.

FIGS. 11A and 11B respectively illustrate a magnetic memory threedimensional (3D) array embodiment of magnetic memory cells using aninterlayer dielectric (IDL) stack in accordance with preferredembodiments. In FIG. 11A, there is shown an interlayer dielectric (IDL)stack generally designated by the reference character 1100. In FIG. 11B,there is shown a magnetic memory three dimensional (3D) array generallydesignated by the reference character 1110 including a plurality ofvertical one dimensional (1D) array 920 of FIG. 9C with multiple wordplanes 1-N (instead of wordlines) shared by all memory cells 500 in aplane level. A respective bitline #1-4 is shared only by memory cells inthe same totem. A resistor 1112 is connected between each of thebitlines #1-4 as shown in FIG. 11B.

FIGS. 12A, 12B and 12C illustrate a three dimensional (3D) arrayembodiment of magnetic memory cells showing respective example steps tocreate one contact per wordplane in accordance with preferredembodiments. In FIG. 12A, a starting structure generally designated bythe reference character 1200 in accordance with preferred embodiments.Starting structure 1200 includes a plurality of word planes 1202separated by a respective interlayer dielectric (IDL) 1204. In FIG. 12B,a single etch step generally designated by the reference character 1210is performed to expose respective spaced-apart word planes 1202. In FIG.12B, a final structure generally designated by the reference character1220 is provided by a first deposition step depositing a dielectric,etching respective holes, and coating the respective holes with an oxidelayer and filling the holes with M1 and M2 magnetic memory cellmaterials with the M1 metal forming respective word plane contacts 1206.

FIGS. 13A, 13B and 13C and FIGS. 14A, 14B, 14C, 14D, and 14E illustraterespective example paths for integration of the three dimensional (3D)array embodiment of magnetic memory cells onto a complementary metaloxide semiconductor (CMOS) wafer in accordance with preferredembodiments.

In FIGS. 13A, 13B and 13C, a first path includes layers of magnetic andinterlayer dielectrics are deposited onto an already finished CMOS waferwith the necessary programming and reading circuitry. An initialstructure generally designated by the reference character 1300 in FIG.13A includes a CMOS wafer 1302. A next structure generally designated bythe reference character 1310 in FIG. 13B includes a stack of layers ofmagnetic and interlayer dielectrics 1312, 1314. A preliminary etchexposes alignment marks already present in the CMOS wafer. Thesealignment marks (not shown) guide a critical etch that createsrespective totems 1306 for depositing the magnetic materials which willform the 3D magnetic memory array generally designated by the referencecharacter 1320 in FIG. 13C.

In FIGS. 14A, 14B, 14C, 14D, and 14E, illustrate a second path 2. InFIGS. 14A and 14B, separate initial structures are respectivelygenerally designated by the reference character 1400, and 1410. In FIG.14A, structure 1400 includes a CMOS wafer 1402 and in FIG. 14B,structure 1410 includes a wafer 1414 including a 3D array of memorycells that are fully finished in separate wafers. In FIG. 14C, a nextstructure generally designated by the reference character 1420 includesthe wafer 1414 including a 3D array of memory cells bonded to the CMOSwafer 1402. For example, the wafers 1402, 1414 are treated with a finishthat includes a capability to develop conductive filaments by electricfield. After both wafer are bonded together in FIG. 14C, the structure1420 is sawed in row of dices, one generally designated by the referencecharacter 1430 in FIG. 14D.

In accordance with features of preferred embodiments, the circuits inthe CMOS and 3D memory array are then activated to form a plurality ofconductive filaments 1440 that will make the necessary electricalconnections for the full functionality of the final memory solutiondie/chip, for example, as shown in example structures respectivelygenerally designated by the reference characters 1442, 1444, and 1446 inFIG. 14E, each including respective conductive filaments 1440. Theconductive filaments 1440 provide robustness against minor misalignmentbetween the wafers 1402, 1414 after bonding.

FIGS. 15A, 15B, 15C, 15D, and 15E illustrate example steps for growingmagnetic memory cells on a complementary metal oxide semiconductor(CMOS) wafer in accordance with preferred embodiments. In FIG. 15A, afirst step generally designated by the reference character 1500 includesa core (biased) including, for example, electroplated grown or columnargrowth of the conductor M2, 1502. Step 1500 may need to exploit shadoweffect and be planned to intercept future CMOS technology node. Forexample, F<20 nm possibly are viable dimensions. In FIG. 15B, a nextstep generally designated by the reference character 1510 includes theconductor M2, 1504 being coated with a non-magnetic spacer layer 1512,such as a Ruthenium layer, and a soft programmable layer or conductorM1, 1514 grown over the pillar including Ru 1512 and conductor M2 1504.A metallic granularity in the magnetic material forming the conductorM1, 1514 is provided to enable or allow better creation of domain wallsso each cylindrical magnetic random access memory (MRAM) cell isindependently programmable. In FIG. 15C, a next step generallydesignated by the reference character 1520 includes, for example, anoxide layer 1522, such as a MgO layer deposited, diminishing the risk ofelectrically shortening columns. In FIG. 15D, a next step generallydesignated by the reference character 1530 includes deposition of ILDlayers 1532 and word plane layers 1534 with anti-parallel vertical bias.In FIG. 15E, a next step generally designated by the reference character1540, for example, includes forming vias 1542, conductive connections1544 and package balls 1546 added.

FIGS. 16A, and 16B illustrate example segregated media based silomagnetic media in accordance with preferred embodiments. In FIG. 16A, atop view of an example segregated media based pillar or silo magneticmemory cell generally designated by the reference character 1600 isshown surrounded by a word plane 1601. The silo magnetic memory cell1600 includes a conductor M1, 1602 and a conductor M2, 1604 separated bya non-magnetic spacer layer 1606, such as Ruthenium layer. An electrontunnel barrier, thin oxide layer 1608 surrounds the conductor M1, 1602.Both conductors 1602, M1, 1604, M2 are electrically conductive andoptionally the conductors 1602, M1, 1604, M2 are formed of magneticmaterials, and the conductor 1604, M2 has a lower resistance and is moreconductive than conductor 102, M1. A set magnetization 1610 isillustrated out of the plane for magnetic conductor 1604, M2. The wordplane 1601 is formed of an electrically conductive and magneticmaterial. A reference layer 1612 is illustrated into the plane for theword plane 1601.

Referring to FIG. 16B, an example array generally designated by thereference character 1620 is shown of the segregated media based silomagnetic media cells 1600 with the word plane 1601 in accordance withpreferred embodiments. Optionally, conductor 1604, M2 is formed of anon-magnetic material, for example, tantalum and conductor 1602, M1 isformed of a magnetic material. The non-magnetic conductor 1604, M2 ismore electrically conductive than magnetic conductor 1602, M1.

Referring to FIGS. 17A, and 17B, there is shown an example arraygenerally designated by the reference character 1700 forming a verticalpillar channel magnetic memory of a plurality of memory cells 1702 inFIG. 17A and a detailed view of one cylindrical memory cell 1702 isshown in FIG. 17B in accordance with preferred embodiments.

In accordance with features of preferred embodiments, each memory cell1702 includes a central conductor M2, 1604 and a conductor M1, 1602,such as shown in FIGS. 16A and 16B. Conductor M1, 1602 is coupled torespective word planes 1-5, 1706, as shown. The word planes 1-5, 1706are reference layers and are separated by interlayer dielectric (IDL)1708. The conductor M1, 1602 has a metallic granularity in the magneticmaterial to enable independently programming the cylindrical magneticrandom access memory (MRAM) cells 1702. Each pillar 1704 includingconductor M1, 1602 and conductor M2, 1604 of the vertical pillar channelmagnetic memory array 1700 are unpatterned. There are no separateetching steps performed on the programmable cell area of conductor M1,1602 within the pillars 1704 at each word plane 1-5, 1706. Theprogrammable cell area of conductor M1, 1602 is capable of beingprogrammed up or down inside each domain of M1 segregated media; thedouble arrow within conductor M1, 1602 can be set upward or set downwardat each word plane level. The arrow within the conductor M2, 1604indicates a direction of magnetization within the conductor M2 that isformed of a magnetic material.

FIGS. 18A, 18B, 18C, 18D and 18E and FIG. 19 illustrate segregated mediaused in programmed media M1 in accordance with preferred embodiments.

Referring to FIGS. 18A, 18B, 18C, 18D and 18E, there are shown examplealternation magnetization variations respectively generally designatedby reference characters 1800, 1810, 1820, 1830 and 1840 of biasedelements of the vertical pillar channel magnetic memory in accordancewith preferred embodiments.

In FIGS. 18A, 18B, 18C, there are shown alternate magnetizationembodiment variations 1800, 1810, and 1820 of biased elements within theprogrammed media or conductor M1, 1602 with conductor M2 formed of amagnetic material. In FIGS. 18D and 18E, there are shown alternatemagnetization embodiment variations 1830, and 1840 of biased elementswithin the programmed media or conductor M1, 1602 with conductor M2formed of a nonmagnetic material.

In accordance with features of preferred embodiments, various desirablemagnetization states can be established with the segregated media usedin the programmed media or conductor M1, 1602.

In accordance with features of preferred embodiments, in FIG. 19, thereis shown a top view of an example segregated media based pillar or silomagnetic memory cell generally designated by the reference character1900 is shown surrounded by a word plane 1601. The silo magnetic memorycell 1900 includes a segregated media conductor M1, 1602 with aplurality of segregated media regions generally designated by thereference character 1902 spaced apart by respective regions 1904.

In accordance with features of preferred embodiments, challenges withcontinuous media in conductor M1, 1602 include, for example, circularmagnetization in programmable media conductor M1, 1602 may force theprogramming to be only viable with Oersted field, and all bits in thevertical pillar are programmable at once. Easy programmability forcebits to require significant magnetic volume with too tall pillars.Segregated media conductor M1, 1602 with a plurality of segregated mediaregions, such as illustrated in FIGS. 20A, and 20B, and FIGS. 21 and 22,mitigates challenges with continuous media in conductor M1, 1602.

Referring now to FIGS. 21 and 22, there are shown a respective top viewof an example segregated media based pillar or silo magnetic memory cellgenerally designated by the reference character 2100, 2200 in accordancewith preferred embodiments. Each silo magnetic memory cell 2100, 2200includes a segregated media conductor M1, 1602 with a plurality ofsegregated media regions generally designated by the reference character2102 with spaced respective regions 2104.

Referring also to FIGS. 20A, and 20B, there are shown examplealternation magnetization embodiment variations respectively generallydesignated by reference characters 2000, 2010 of biased elements ofsegregated media conductor M1, 1602 with the plurality of segregatedmedia regions or domains 2102 of FIGS. 21 and 22 in accordance withpreferred embodiments. In FIG. 20A, the example alternationmagnetization embodiment variation 2000 illustrates possible programmingup or down inside of each domain 2102. In FIG. 20B, the examplealternation magnetization embodiment variation 2010 illustrates possibleprogramming side to side inside of each domain 2102.

While the present invention has been described with reference to thedetails of the embodiments of the invention shown in the drawing, thesedetails are not intended to limit the scope of the invention as claimedin the appended claims.

What is claimed is:
 1. A method for implementing a magnetic memory arraycomprising: forming a plurality of magnetic pillar memory cells includesa first conductor M1 being formed of a magnetic material, and a secondconductor M2 being more electrically conductive than said conductor M1including: growing said second conductor M2; coating said secondconductor M2 with a non-magnetic spacer layer; growing said firstmagnetic conductor M1 over said coated second conductor M2; depositingan oxide barrier over said grown first magnetic conductor M1 formingmagnetic pillar memory cells; and depositing an interlayer dielectric(IDL) stack of word planes separated by a respective IDL on the firstmagnetic conductor M1, wherein the word planes have a magnetizationstate anti-parallel to a magnetization state of the second conductor M2;wherein the first conductor M1 is programmable to a parallel andanti-parallel magnetization state.
 2. The method as recited in claim 1wherein growing said second conductor M2 includes forming said secondconductor M2 of a magnetic material.
 3. The method as recited in claim 1wherein growing said second conductor M2 includes forming said secondconductor M2 of a non-magnetic material.
 4. The method are recited inclaim 1 includes sharing a bit line only by said magnetic pillar memorycells inside said respective pillar holes.
 5. The method as recited inclaim 1 wherein forming said magnetic pillar memory cells includesproviding a complementary metal oxide semiconductor (CMOS) wafer havinga CMOS defined pad pattern, and growing said magnetic pillar memorycells on said CMOS defined pad pattern.
 6. The method as recited inclaim 5 includes treating said CMOS defined pad pattern for providing asource of growth for said plurality of magnetic pillar memory cells. 7.The method as recited in claim 1 including forming vias in said IDLstack, and forming other conductive electrical connections.
 8. Themethod as recited in claim 1 wherein growing said second conductor M2and growing said first conductor M1 includes each said first conductorM1 and said second conductor M2 not being patterned.
 9. A method forimplementing a magnetic memory array comprising: forming a plurality ofmagnetic pillar memory cells includes a first conductor M1 being formedof a magnetic material, and a second conductor M2 being moreelectrically conductive than said conductor M1 including: growing saidsecond conductor M2; coating said second conductor M2 with anon-magnetic spacer layer; growing said first magnetic conductor M1 oversaid coated second conductor M2; depositing an oxide barrier over saidgrown first magnetic conductor M1 forming magnetic pillar memory cells;and depositing an interlayer dielectric (IDL) stack of word planesseparated by a respective IDL wherein growing said first conductor M1includes forming said first conductor M1 of said magnetic materialhaving a metallic granularity enabling independent programming of eachsaid magnetic pillar memory cell.
 10. A method for implementing amagnetic memory array comprising: forming a plurality of magnetic pillarmemory cells includes a first conductor M1 being formed of a magneticmaterial, and a second conductor M2 being more electrically conductivethan said conductor M1 including: growing said second conductor M2;coating said second conductor M2 with a non-magnetic spacer layer;growing said first magnetic conductor M1 over said coated secondconductor M2; depositing an oxide barrier over said grown first magneticconductor M1 forming magnetic pillar memory cells; and depositing aninterlayer dielectric (IDL) stack of word planes separated by arespective IDL includes sharing each said respective word plane by allmagnetic pillar memory cells in a respective plane level.